Pressure vessels are well known and are used, for instance, for the storage of Compressed Natural Gas (CNG) as fuel in motor vehicles. Pressure vessels of this type may include an inner container, also referred to as a “liner”, which is wrapped with a fibre material. It is known to provide in the pressure vessel metal parts, which may serve, in particular, to receive fittings, such as valves, and are also referred to as a “boss”. For the production of the inner container, the extrusion blow molding method, in which an extruded tubular preform is blow-molded, may for instance be used.
German Patent Publication No. DE 10 2011 116 553 A1, for example, discloses a method for producing a composite pressure vessel having an inner container made of thermoplastic plastic, at least one pole piece provided in a neck region, and having a winding, made of a fibre material, which reinforces the inner container, wherein the method comprises the production of the inner container by extrusion blow molding, wherein the pole piece, in the formation of the inner container, is molded onto the inner container, such that the pole piece is at least partially enclosed by the inner container. The pole piece is of two-part configuration and comprises a pole cap arranged outside the inner container, wherein the wall of the inner container is clamped in place in the neck region between the pole piece and the pole cap. Following completion of the inner container, the pole piece is secured from outside against the wall of the container with a locking element.